Portable radio transceivers or “walkie-talkies” are able to establish either one-to-one or one-to-many communication links. Such radio transceivers are indispensable for law enforcement, rescue, and military personnel, and have even become commonplace across various business environments as well as for recreational activities. In particular, radio transceivers provide a near instantaneous connection between users in a talk group by utilizing push to talk (PTT) communications over a half-duplex radio transmission system, for example, over a circuit-switched network. Half-duplex radio transmission systems provide two-way communication on a single radio channel thus limiting speaking privileges to one user at a time. Therefore, requests to speak in a PTT communication session are handled by a floor control mechanism at a PTT server.
Recent advances in cellular packet-switched networks have resulted in the development of a push to talk over cellular (PoC) solution, for example, as described in PoC V2.0 Enabler Package released Sep. 22, 2009 by Open Mobile Alliance (OMA). Specifically, a PoC network provides a half-duplex voice over internet protocol (VoIP) solution, with well-known PTT functionality. PoC may be implemented on an internet protocol multimedia subsystem (IMS) platform, as described in 3GPP Technical Specification (TS) 23.228, and any subsequent revisions. The floor control mechanism in a PoC system resides in a PoC server above the IMS platform. Moreover, PoC employs familiar protocols for voice and control signaling, including Real-Time Transport Protocol (RTP), as described, for example, in Request for Comments (RFC) 3550 dated July 2003 by Internet Engineering Task Force (IETF), and any subsequent revisions, and Session Initiation Protocol (SIP), for example, as described in RFC 3261 published June 2002 by IETF Network Working Group and any subsequent revisions.
Typically, the identity of the transmitter is transmitted in SIP messages or floor control messages to convey the identity of a user. The received ID code is then associated with a particular user by matching the ID code with a registered user in a memory of the receiver and then displayed at the receiver. During a communication session that supports a privacy feature, such as during a PoC communication session, it may desirable to hide the user's identity from other participants of the communication session. Presently, a group participant is able to request anonymity when initiating or joining a communication session. Once anonymity is requested, the participant's identity is hidden for all instances during the communication session.
However, it may be desirable during a group communication session to hide a participant's identity under certain circumstances and to show the same participant's identity under other circumstances. Accordingly, there is a need for a system and method of increasing the granularity of controlling identity privacy in a group communication session.
Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help improve understanding of various embodiments. In addition, the description and drawings do not necessarily require the order illustrated. It will be further appreciated that certain actions and/or steps may be described or depicted in a particular order of occurrence while those skilled in the art will understand that such specificity with respect to sequence is not actually required.
Apparatus and method components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the various embodiments so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein. Thus, it will be appreciated that for simplicity and clarity of illustration, common and well-understood elements that are useful or necessary in a commercially feasible embodiment may not be depicted in order to facilitate a less obstructed view of these various embodiments.